Method and apparatus for drilling oil and gas wells.



E. E. SHAFFER.

METHOD AND APPARATUS FOR DRILLING OIL AND GAS WELLS.

APPLICATION FILED FEB. \5, 1915.

1,166,01 1. Patented Dec. 28, 1915.

3 SHEETSSHEET I.

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Ulillllli I NV a N T n R WITNEEIEIEEI 241V 'wdflfw HTTURNEYE E. E. SHAFFER.

METHOD AND APPARATUS FOR DRILLING OIL AND GAS WELLS.

APPLICATION FILED FEB. 15. IBIS.

1,166,01 1, Patented Dec. 28, 1915.

3 SHEETS-SHEET 2.

ATTDRNEYb E. E. SHAFFER.

METHOD AND APPARATUS FOR DRILLING OIL AND GAS WELLS.

APPLICATION FILED FEB. 15, I915.

Patented Dec. 1915.

3 SHEETS-SHEET 3. F: :15.

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A v 5 5.5.2 Inna-2i I shale and lime shells.

UNITED STATES PATENT OFFICE.

ELMER E. SHAFFER, 0F TULSA, OKLAHOMA.

METHOD AND APPARATUS FOR DRILLING OIL AND GAS WELLS.

Application filed February 15, 1915.

To all whom it may concern:

Be it known that I, Emmi: E. SHAFFER, a. citizen of the United States, residing at Tulsa, in the county of Tulsa and State of Oklahoma. have invented new and useful Improvements in Methods and Apparatus for Drilling Oil and Gas lVells, of which the following is a specification.

This invention relates to an improved method and apparatus for drilling oil and gas wells which I have termed the standard rotary drilling outfit in that it combines the desirable features of the so-called standard and rotary outfits, it being well known that for drilling through mud and loose sands or other soft formations the rotary method is superior to the standard or reciprocating, while for drilling hard rock formations the standard or concussion outfit is more rapid in action than the rotary. The apparatus is especially desirable for drilling in coast countries and other localities where the formations are largely soft and intermingled with Ordinarily the casing consists of strings or sections of ipe gradually decreasing in diameterQsay. rom a maximum of about fifteen and fone-half inches to a minimum of four and one-half inches. This construction requires separate sets of different sized drilling tools, one for each size of pipe,.repdering the equipment corresponding]yexpensive. The stems for rotary tools requiie a. large quantity of pipe which constitutes al material part of the cost of the outfit, while the pulling out of the stem to change the bits or tools involves a considerable item of time and labor.

One of the objects of my invention is the provision of a relatively inexpensive combination outfit of this kind which can be readily converted from the standard to the rotary form or vice versa, in order to utilize the recognized advantages of each, accordin to the nature of the formations.

A furt er object is to so construct the casing that but a single size or set of drilling tools is required, and further to utilize the casing of the standard outfit as a driver or rotating means for the rotary drilling tools, thus dispensing with the usual separate drill stem and saving its cost and the time and labor required to Withdraw and replace it in changing the tools.

Further objects are to improve the ap- Specification of Letters Patent.

Patented Dec. 28, 1915.

Serial No. 8,329.

paratus in various other respects as will hereinafter appear.

In the accompanying drawings: Figure 1 is a sectional elevation of the improved apparatus assembled as a rotary outfit. Fig. 2 is an enlarged sectional elevation of the mechanism for rotating the casing, the flushhead and intermediate parts. Fig. 3 is a vertical section. on an enlarged scale, of the flush-head. Fig. 4 is a horizontal section on lines l-l, Fig. 2. Fig. 5 is a similar section on line Fig. 2. Fig. 6 is an enlarged sectional elevation of the rotary casing, the tool-socket and the means for coupling the latter to the pipe. Fig. 7 is a. sectional elevation of said tool socket on a still larger scale, showing the position of its movable parts while the socket is being lowered through the rotary casing. Fig. 8 is a. simi lar view showing the tool socket lowered and coupled to the casing. Fig. 9 is a vertlcal section at right angles to Fig. 8. Figs. 10 and 11 are horizontal sections on the correspondinglynumbered lines in Fig. 8. Fig. 12 is an enlarged vertical section of the coupling sleeve with which the coupling members of the tool socket cooperate. Fig. 13 is a perspective view of one of the clutchblocks of the tool socket. Fig. 14 is a similar view of one of the stop-dogs of said socket.

Similar characters of reference indicate corresponding parts throughout the several views.

1 indicates the usual derrick; 2 its main or floor-sills: 3 the walking beam; 4 the pitman shown detached from the crank shaft which latter carries the band wheel 5; (3 the bull wheel: 7 the sand reel and h the usual pumps. These several parts mav be of any suitable or well known construetion.

9 indicates a horizontal table-gear such as ordinarily employed in rotary drilling outfits. the same being supported by a roller bearing 10 mounted on sills 11 or other supports, preferably arranged below the main derrick sills This table-gear is driven by the pinion 12, the shaft 13 of which may be connected with the driving shaft ll by the usual clutch 15. Mounted upon this table-gear are the customary clutch wheels or rollers 16 adapted to grip the part to be rotated which in the present case is the well casing 17, so as to compel said casing to rotate with the table-gear 9 and at the same time allow the casing to move up or down through it. The shafts of these rollers are mounted in movable bearings 18 which are adjusted by the usual screws 19 to cause the rollers to grip said pipe.

20 indicates the usual drive-pipe of the well which is sunk to a suitable depth in any well known manner. Through this casing is lowered the wellrasing 17 which is sufli cientiy smaller in diameter than the casing 20 to permit the slush or mud to ascend between these pipes into the customary slushdischarge pipe 2L For example, the drivepipe may be twelve and one-half inches and the casing eight inches in diameter. This casing is adapted to extend from the top to the bottom of the well and to serve not only as an oil discharge pipe but also as a tool or drill-stem which is rotated by the table-gear 9 and in turn rotates the underreamer 2:2 or other rotary tools, such as a re commonly used for drilling through sand or mud formations and ordinary rock formations. such tools being carried by a tool socket or head adapted to be coupled to the rotary casing by suitable coupling or clutch means. thus dispensing with the usual sepa rate tool-stems heretofore employed in addition to the non-rotary casing. These cou pling devices will be hereinafter more fully described.

The casing LT consists of sections of suit able length connected by couplings of any suitable construction, the coupling :23 shown in the drawings being the lowermost one of the casing. instead of being composed of strings of dili'erent-sized pipe, as heretofore. the entire casing preferably consits of pipe lengths of uniform size, say eight-inch pipe. At its lower end the rotary casing is adapted to carry a shoe 2% or other suitable drilling tool which bores the well-hole in advance of the casing and is rotated by its rigid connection therewith. This shoe may be of any suitable construction. That shown in the drawings forms the subject of a separate application about to be filed by me and comprises an upwardly-tapering perforated tube, screwed upon the lower end of the *asing and provided with spiral rows of openings 25 extending from the lower edge nearly to the top of the tube. The openings of the lowermost rows are partial or mutilated openings. so that their lateral portions form the cutting edges of the shoe. By this construction before the lowermost openings are wholly worn away, those of the succeeding row come into action and in turn form the cutting edge, thus rendering the too] selfsharpening.

The upper portion of the casing 17 extends centrally through a vertically-movable spider or plate 26 which in the preferred constru'ction shown in the drawings, is carried by the plungers 2? of hydraulic jachs .28, whereby the spider and the casing 17 suspended therefrom may be raised-or low cred by forcing liquid into said barrels or allowing it to exhaust therefrom. For this purpose. the lower ends of the several barrels of the jacks may be connected with a hollow supporting base 29 to which liuid under the required high pressure is supplied by a hydraulic pump, not shown, through a pipe 29*, which may also serve as a drain or discharge pipe by the use of suitable valves. These jacks are preferably arranged in a pit 30 in order to bring the spider :Zfi about on a level with the derrick floor and the table gear 9 below it. Mounted upon said spider is a suitable anti-friction bearing which in the construction shown consists of a lower nonrotary ring or plate 31 and an upper rotary ring or plate 32. these rings containing races in which conical rollers 33 run. This rotary ring contains a divided plug or bushing til through which the upper portion of the his ing passes. llemovably attached to the screw threaded upper end of the casing is a flush head 3.13 of any suitable construction and in tcrposcd between this lush-head and the plug 34 is an elevator ill; of any appropriate construction. Thecou pl ing-colla r 3T between the flush-head and the upper end of the casing forms a stop which rests upon the elevator :50, which in turn is supported by the upper ring 32 of the cone-bearing, whereby the ilushhead and the elevator are free to rotate with the casing relatively to the spider so. In the preferred construction shown in the drawings, Figs. 2 and $5. the flush-head ('Ulllprises a lower stuiiing box 3H. an upper stutling box 259 and an externaHy-thremlcd tube or sleeve l0 connecting said boxes. Passing axially through these stalling boxes is an inlet or flushing pipe 41 which extends into the upper end of the casing while its projecting upper end has an elbow +2 to which is attached the hose 43 or other conduit connected with the slush-pumps H. This construction while forming a tight joint permits the llush-head 3? to rotate on the stationary inlet pipe l1. To prevent longitudinal displacement of this pipe in the flush-head. it is provided within the cap ll of the head with a collar 45 which is interposed between the upper end of the shilling box 3%) and the lower ring lb of an antifrlction bearing. preferably of the ball type seated in the upper end of said cap. as shown in Fig. 3. This ball bearing receives the upward thrust against the pipe 41 due to the back pressure of the water therein. reducing friction between the rotary flush head and said pipe and preventing the latter from turning with the head. i

In the pret'm'rcd construction of the elevator as shown in the drawings. the same is divided vertically into two sections hinged together at their rear ends by a vertical pin 47 and detachably connected at their opposite ends by a latch or locking device -l9 of any suitable or well known construction. livoted to opposite sides of the elevator are the customary links 50 adapted to engage the usual derrick-tackle for pulling up the casing 17. To permit the removal of these links so as to be out of the way when not in use, the elevator is provided with downwardly-opening seats or sockets 51 for the inner cross bars of the links, which sockets are normally closed by caps,52 held in place by bolts 53 or other suitable means to permit the ready removal of the caps and links.

5a indicates a tool socket or head which is adapted to be lowered through the casing 17, nearly to its lower end, and to the lower end of which the under-reamer 22 or other rotary tool is attached by any suitable means, the preferred means being a tube 55 connected with the under-reamer and the tool' socket by couplings 56-. At its upper end this tool socket is provided with a comparatively short upwardly-extending shank or stem 57 having a head 58 adapted to be engaged by a horn-socket or other suitable tool by which it is lowered into the casing andwithdrawn therefrom. A tool of this character is shown and described in a separate application for patent about to be filed by me.

Located in recesses in opposite sides of the tool-socket. ar its lower end, are a pair of stop-dogs or fiawls 59 pivoted between their ends on horizontal pins 60 carried by the socket. The lower ends of these dogs are normally retracted to the position shown in Fig. 7 in which they permit the tool socket to be freely lowered through the casing 17. When the lower ends of the dogs are swung outward, as shown in Figs. 6 and 8, they are adapted to engage with and be stopped by a toothed ring or shoulder 61 arranged within the casing at a suitable distance from its lower end. This ring preferably forms part of the lowermost coupling 23 of the casing, as best shown in Figs. 8, 9 and 12. When thus expanded, these dogs by striking the toothed-ring (i1 arrest the descending tool socket at the desired depth. Extending across the upper ends of the dogs is a ver'tically-sliding key or cam-bar 63 guided in vertical slots 64 in the tool socket and provided with beveled faces 65 which respectively engage the outer sides of the dogs, so that when the cam-bar is depressed from the position shown in'Fig. 7 to that shown in Fig. 8, it forces the upper arms of the dogs inwardly, thereby throwing their lower arms outwardly ready to engage the toothed stop-ring 61. This cam-bar is constantly drawn downward by a spring (36 bearing at its upper end against an abutment 67 of the tool socket and at its lower end against a tube or sleeve 68. This tube slides in a longitudinal chamber 69 in the lower portion of the tool-socket and bears at its lower end against a nut or projection 70 on a rod or bolt 71 which slides in the abutment ()T and is provided in its upper portion with a. longitudinal slot 72 through which the cam-bar 63 passes. This spring thus tends constantly to depress the cam-bar (33 through the medium of the tube 68 and the bolt 71.

The large upper portion of the tool socket is hollow to receive a vertically-movable wedge 73 to which the lower end of the stem 57 is secured. This stem slides in an opening formed centrally in a cap '74 applied to the upper end of the tool-socket. The wedge 73 is interposed between a pair of radiallysliding clutch-blocks or members 75 which are guided in a slot'76 formed in the adjacent portion of the tool head. These clutch blocks are preferably interlocked with said wedge in such manner that when the wedge is lowered relatively to the blocks they are forced outwardly while when the wedge is raised, the blocks are retracted. For this purpose, the wedge is preferably provided on opposite sides with undercut tenons 77 which engage corresponding grooves 78 in the backs of the blocks, as shown in Fig. 10. To center the wedge in the tool-socket during its movements, the same is provided in its sides with vertical grooves 79 which receive horizontal guide pins 80 carried by the body of the tool socket, as shown in Figs. 9 and 10. The clutch blocks are provided in their outer faces with vertical ribs, teeth or flutes 81 preferably of V-shaped cross section, as shown in Figs. 10 and 13. These ribs are adapted to interlock with an annular series of corresponding ribs 01' teeth 82 arranged lengthwise on the inner side of the coupling section 23 of the casing, whereby the rotary movement of the casing is transmitted to the tool socket and the tool carried by it, the cooperating ribs of the casing and the blocks 75 thus practically constituting clutch members which, when interlocked, drive the tool socket from the rotary pipe and when disengaged allow the casing to turn independently of the tool socket. As shown in Figs. 8 and 9, the portion of the coupling section 23 located between its ribs 82 and stop-teeth 61, is of somewhat greater internal diameter than the portions thereof carrying said ribs and teeth, the last-named portions being substantially of the same internal diameter as the pipe-sections of the casing 17. By this construction, the dogs 59 are held in their retracted positionby contact with the interior of the casing during the lowering of the tool socket and remain in that position until they pass below the ribs 82, when. owing to the enlarged diameter of the coupling section 23, they are allowed to swing out under the ten sion of the spring 66 exerted through the cam-bar 63. By the continued lowering of the tool-socket, the expanded dogs encounter the toothed ring 31 which arrests the socket, as hereinbeiore described. While thus lowering the tool socket, the wedge 73 is withdrawn to the position shown in Fig. 7, 1n which its large endbears against the cap 74 of the tool socket. The tool socket is therefore suspended from this wedge and the stem 57 during this lowering operation and the parts remain in this position until the expanded dogs are arrested by the toothed ring 61; whereupon the wedge continues to descend by gravity independently of the arrested socket. thereby spreading the clutch blocks T5 into engagement with the teeth 82 and coupling the tool socket to the rotary casing 17. as before described. The stop ring (it is located at the proper distance below the clutch ribs 82 to arrest the toolsocket when the clutch blocks arrive opposite the ribs. The teeth of this stop-ring are arranged at its upper edge and are V-shaped, and the stop-dogs are provided at their lower ends with corresponding teeth 59 adapted to engage those of the ring. The teeth of the ring are so arranged relative to the coupling ribs 82 that in case the ribs of the clutch blocks. in lowering the tool socket fail to mesh with the ribs the toothed dogs upon engaging with the teeth of the stop ring (31 will be deflected laterally by the inclined sides of the teeth, thereby rotating the tool-socket sutliciently to bring said ribs into proper mesh. The ribs of the clutch blocks are thus prevented from mounting those of the rotary casing, insuring the proper coupling of the tool socket to the casing. it is obvious, however, that so far as the stop function of the ring 61 is concerned, its teeth are not necessary. By employing stop-devices of this kind which are separate from and independent of the clutch blocks 75, the stop devices carry the weight of the tool socket when the latter is lowered to the proper depth to engage the ribs 82 of the casing, thus relieving the clutch blocks from such weight. leaving them free to slide in and out with comparatively little friction and rendering them reliable in action. Upon elevating the tool socket through the casing 17, the dogs on coming in contact with the ribs 82 of the coupling section are forced inward to their retracted position, permitting the tool to be withdrawn from the easing without restraint. By this inward movement of the lower arms of the dogs their upper ends force the cam-bar 63 by bearing against its beveled faces 65, thereby pulling the bolt 71 and the tube 68 upward and again tensioning the spring 66. As shown. the coupling sleeve 23 is preferably located some distance above or remote from the shoe or lower end of the casing. By this arrangement, the coupling devices which connect the tool-socket to the rotary casing are a suflicient distance from the shoe and bit to avoid the liability of their becoming clogged with mud, insuring the reliable action of the coupling devices at all times.

As shown in Figs. 7, 8 and 9. the tool socket is provided near its lower end with suitable packing 83 which bears against the surrounding well-casing to check the descent of the flushing water between it and the tool.

85 indicates one or more descending water passages extending inwardly from the periphery of the tool-socket at a point above the packing 83 and thence downwardly through the central portion of the socket to the tube 55 for supplying water to the under-reamer bit.

In order to allow the water to pass up through the tool-socket and permit it to be lowered quickly, the socket is provided with a number of longitudinal relief passages 8% extending from its bottom to a point above the packing Upwardly-opening check valves 86 are applied to the upper ends of these relief passages to prevent the water from descending through them instead of through the bit-supplying passages 85.

The operation of the apparatus is as follows: The drive pipe 20 is sunk in the usual manner. \Vhe'n the apparatus is to be used as a rotary outfit. its parts are assembled as shown in the drawings, the flush head 35 being connected to the upper end of the casing 17 and the latter clutched to the rotary head or table gear 9, so as to be rotated thereby, as hereinl'ietore described. The rotary shoe 24 of the casing drills a hole larger than the external diameter of the casing. leaving a passage around the casing through which the drillings are flushed into the discharge pipe :21 by the stream of water forced through the casing by the pumps. As the drilling proceeds, the casing which is carried by the hydraulic jacks 28 is fed downward gradually by draining the water from the jacks. Any other rotary tools to befused, such as the under-reamer 22, are attached to the tool-socket 54 which is lowered through the casing by a cable, cable tools and a suit able horn socket or similar implement, and automatically coupled to the rotary casing, as hereinbefore described, to drive the same from the casing, instead of by the separate. drill or anger stem ordinarily employed. By the same horn socket, this rotary tool may be uncoupled from the casing and withdrawn therefrom and another rotary tool substituted therefor, as required. New lengths of casing or pipe are added by first removing the flush'head. 35 from the stop-collar 37 and attaching said head by a sinilar stop collar to a new length of pipe. A second elevator the same as the elevator 36 is then put over the stop collar of the new pipedength and the flush head is raised with derrick tackle attached to said second elevator. The added length of pipe is next screwed into the stopcollar 37 of the casing 17 and the latter is raised by the derrick tackle sufficiently to permit the removal of the first elevator 36, the casing 17 being suspended by said second elevator attached to the derrick-tackle. By means of the hydraulic jacks, the spider 26 and the swivel or bearing composed of the parts 31, 3'2 and 33 are then raised to meet said second elevator, which together with the casing are meanwhile sustained by the derrick tackle. The derrick tackle is then detached and the casing is again supported by the jacks.

In using the apparatus with standard or concussion drilling tools, the flush-head 35 is removed from the casing, the underreamer or other rotary tool is withdrawn by means of said cable, cable tools and horn socket, a standard bit or tool is substituted for said horn socket and said cable tools and bit are then lowered through the casing and actuated in the customary manner, the bit drilling some distance in advance of the lower end of the casing.

As shown in the drawings, the table-gear 9 is preferably located below the level of the derrick-floor 2. This arrangement avoids the necessity of removing said gear when using the standard outfit and enables the operator to keep the casing rotating while drilling with the standard tools, preventing the casing from freezing during the operation of the standard tools.

In drilling through soft formations or such as are intermingled with shale or lime shells, the apparatus is converted into the rotary form, while upon encountering hard rock formations the standard equipment is employed, the change from one to the other being made in a comparatively short time. In drilling through hard formations with the reciprocating or cable tools, the rotary feature of the casing affords the important advantage that the hole drilled by such tools may be enlarged or under-reamed by the shoe 24 to the external diameter of the casing by rotating the casing, thereby permitting the latter to be sunk to the bottom of the hole drilled by the cable tools.

As before stated, this improved method and apparatus permit the use of a casing of uniform diameter throughout its depth and constructed of medium sized pipe, such as eight-inch, instead of requiring numerous strings or sections of progressively smaller diameter. This results in an important sav ing in the cost of ipe, and also in tools, as only one full set of a single size is requlred, instead of numerous different-sized sets for the different-sized pipes ordinarily used. Furthermore, the coupling and uncoupling of the pipe-sections forming the ordinary rotary drill stem require considerable time, and as the present apparatus does away with that stem, it saves not only that item of labor but also the cost of the large amount of pipe required for the different-sized drillstems, as well as the transportation charges and duty on the same. Compared with the ordinary standard outfit, this improved apparatus saves more than seventy per cent. of the casing-pipe and fifty per cent. of the labor, and compared with the ordinary rotary outfit, it saves more than sixty per cent. of the casing-pipe and seventy per cent. of the labor. With this improved outfit. the bits can moreover, be changed in from ten to thirty minutes, according to the depth, whereas with the rotary outfits now in use, such change requires from one hour to one day. This apparatus has the further advantage that when the well is finished, the 021s ing is already set, thus saving from a day to a week over the ordinary rotary methods in use, which require the well to be washed out and reamed down to set the casing. The casing can also be more reliably cemented in the lime or oil-sand, as the drilling can be continued with the'shoe in the lime, and on account of its perforated and upwardlytapering construction, the shoe can be fastened in the lime as securely as the lime itself. Furthermore, the annoyance of mud blow outs from gas is avoided, as the casing is carried down as fast as it drills its hole and the mud is promptly piped off. Again, with this outfit, thecasing may be kept rotating in the mud while changing bits, avoiding all danger of freezing up while making the change. As regards fishing for tools, there is also an important saving over ordinary outfits, as a fishing job is never in the mud but always inside of the casing. The draining of the hydraulic jacks can be regulated to feed the rotary casing a small fraction of an inch at a time, thus effectually guarding against twisting oil the casing which practically forms the stem of the drilling tool.

It is obvious that the apparatus may be modified in various respects within the scope of the appended claims, and I do not therefore wish to be limited to the particular construction herein shown and described.

I prefer to employ in connection with this well drilling apparatus, the collapsible rotary under-reamer bit and the horn socket shown and described in separate applications for patent filed by me on the 15th day of February, 1915, Serial No. 8326 and No. 8327, respectively, but other suitable rotary tools" and any other suitable horn socket may be used, if desired.

I claim as my invention:

1. The herein described method of drilling Wells, which consists in sinking a cas1ng into the well-hole, lowering a drilling bit through the casing and reciprocating the same by a cable and cable tools, and at the same time rotating the casing to prevent freezing thereof during said drilling operation.

2. The herein described method of drilling a well, which consists in sinking into the well a casing provided with a shoe, drilling hard formations by lowering a cable and cable tools through said casing and reciprocating the same therein, and then rotating the casing and shoe to underream the wellhole and allow the casing to be sunk to the bottom of the hole drilled by said cable tools.

3. A combined rotary and reciprocating drilling apparatus for oil wells, comprising a casing arranged in the well, means for rotating the casing, a stemless rotary drilling tool, means for coupling said tool to the casing lto turn therewith, said casing having a su cient internal diameter throughout its depth to permit the tools and drill-bit of a reciprocating outfit to be lowered therethrough.

4. In a well drilling apparatus, the combination of a casing arranged in the Well, means for rotating said casing, a seamless drilling tool, and means remote from the lower end of the casing for coupling said tool to the casing to turn therewith.

5. In an apparatus for drilling oil wells, the combination of a casing arranged in the well and having an internal stop, means for rotating said casing, a tool-socket having a retractable member adapted to engage said stop when projected, and means carried by the tool socket and separate from said retractable member for coupling the tool socket to the rotary casing.

6. In an apparatus for drilling oil wells, the combination of a casing arranged in the well and having an internal stop, means for rotating said casing, a tool-socket having outwardly-swinging dogs arranged to engage said stop, a spring for projecting said dogs, and means carried by the tool socket for coupling the same to the rotary casing.

7. In an apparatus for drilling oil wells, the combination of a rotatable casing arranged in the well and provided with an internal stop and above said stop with coupling means, means for rotating said casing, and a toohsocket provided with a'retractable stop-member adapted to engage said stop when projected and above said member with coupling means adapted to engage with the first-named coupling means, said internal stop having meansfor automatically turning the tool-socket in the casing to bring the coupling means of the casing and the tool-socket into proper mesh.

8. In an apparatus for drilling oil wells, the combination of a rotatable casing arranged in the well and provided with an internal stop having V-shaped teeth and above said teeth with coupling-ribs, means for rotating said casing, and a tool-socket provided with toothed outwardly-movable dogs adapted to engage said toothed stop and above said dogs with toothed clutch blocks cooperating with said coupling ribs.

9. In an apparatus for drilling oil Wells, the combination of a casing arranged in the well and provided with an internal stop and above said stop with a clutch member, means for rotating said casing, and a tool socket having a retractable member coiiperating with said stop and a clutch-member cooperating with the first-named clutchmember to drive the tool-socket from the casing.

10. In an apparatus for drilling oil wells, the combination of a casing arranged in the well and provided with an internal stop-shoulder and above said shoulder with longitudinal clutch-ribs, means for rotating said casing, and a tool-socket having retractable dogs arranged to engage said shoulder when projected, clutch-blocks arranged to engage said clutch-ribs and a wedgeinterposed between said blocks.

11. In a well-drilling apparatus, a tool socket having outwardly-swinging stopdogs, a cam-bar slidable vertically in the body of the socket and bearing against the upper ends of said dogs, and a spring for depressing said cam-bar.

12. In a well-drilling apparatus, a tool socket having outwardly-swinging stopdogs, a cam-bar slidable vertically in the body of the socket and bearing against the upper ends of said dogs, a rod engaging said cam-bar and arranged to slide lengthwise of the tool-socket, said rod carrying a projection, and a spring applied to said rod and bearing at one end against said projection and at its other end against the body of the tool socket.

13. In a well-drillin apparatus, a coupling sleeve adapted to orm a section of the well-casing and having an internal stop arranged to be engaged by a corresponding member of a tool-socket and a clutch-member separate from and above said stop arranged to be engaged by a cooperating member of the tool-socket.

14. In a well-drilling apparatus, a coupling sleeve adapted to form a section of the well-casing and provided with an internal toothed stop-shoulder and above said shtgulder with internal longitudinal clutchn s. i

15. In a well-drilling apparatus a toolsocket having a descending water passage extending inwardly from its periphery and thence downwardly through its central portion, an ascending relief-passage extending upwardly from its lower end, and an upwardly-opening check-valve applied to said relief-passage.

16. In a well-drilling apparatus, the combination of the derrick-floor, a hydraulic jack having its cylinders arranged below said floor, and a supporting-plate mounted on said jack and adapted to carry the wellcaslng.

17. In a well-drilling apparatus, the combination of a supporting plate, means for raising and lowerlng said plate, and antifriction hearing resting on said plate, and an elevator supported on said bearing and adapted to carry a rotary well-casing.

18. In a well-drilling apparatus, the combination of a supporting plate, means for raising and lowering said plate, an antifriction bearing resting on said plate, a Wellcasing passing through said plate and said bearing, an elevator mounted on said bearing and applied to said casing, and a flush head attached to the upper end of the casing.

Vitness my hand this 6th day of February, 1915.

ELMER E. SHAFFER. Witnesses:

CHAS. F. Blsn'm', W. H. MANDEVILLE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0.

It is hereby certiiied that in Letters Patent No. 1,166,011, granted December 28, 1915, upon the application of Elmer E. Shaffer, of Tulsa, Oklahoma, for an improvement in Methods and Apparatus for Drilling Oil and Gas Wells," an

error appears in the printed specification requiring correction as follows: Page 6,

line 27, claim 4, for the word "seamless read stemless; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 18th day of January, A. D., 1916.

[man] J. T. NEWTON,

Acting C'ommiuioner of Patents. Cl. 255-: 

